Online PHP editor | output for qZ0bN

Output for 8.2.0 - 8.2.18, 8.3.0 - 8.3.6: Fatal error: Uncaught TypeError: strtoupper(): Argument #1 ($string) must be of type string, array given in /in/qZ0bN:12 Stack trace: #0 /in/qZ0bN(12): strtoupper(Array) #1 [internal function]: {closure}(Array) #2 /in/qZ0bN(6): preg_replace_callback('/(_[a-z])/', Object(Closure), 'rob_tr') #3 {main} thrown in /in/qZ0bN on line 12
Process exited with code 255.
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28: Fatal error: Uncaught TypeError: strtoupper(): Argument #1 ($string) must be of type string, array given in /in/qZ0bN:12 Stack trace: #0 /in/qZ0bN(12): strtoupper(Array) #1 [internal function]: {closure}(Array) #2 /in/qZ0bN(15): preg_replace_callback('/(_[a-z])/', Object(Closure), 'rob_tr') #3 {main} thrown in /in/qZ0bN on line 12
Process exited with code 255.
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33: Warning: strtoupper() expects parameter 1 to be string, array given in /in/qZ0bN on line 12 robr
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17: Parse error: syntax error, unexpected T_FUNCTION in /in/qZ0bN on line 6
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1, 5.0.0 - 5.0.5: Parse error: parse error, unexpected T_FUNCTION in /in/qZ0bN on line 6
Process exited with code 255.
Output for 4.3.2 - 4.3.4: Parse error: parse error in /in/qZ0bN on line 6
Process exited with code 255.